The present invention relates to a cable for handling systems and in particular of the radial disk type for entrainment of materials with essentially fluid behavior inside tubular ducts within which the cable runs, for example for distribution of feed in animal breeding farms or for handling of generally powdery or granular materials in industrial plants.
In systems of this type it is required that the cable be essentially inextensible in the direction of motion and have high flexibility and wear resistance.
To produce cables with these characteristics it is advantageous to use a core consisting of a plurality of strands woven together loosely in a direction near the axis of the cable and cover it with a sheath consisting of a thick wefted strand mesh braided at a high angle with respect to the cable axis.
But the radial members commonly used for handling loose materials cannot be molded on cables made in this manner. Indeed, under these conditions the radial handling members are constrained only to the external sheath and the stresses to which they are subject are not born by the cable core which is the strongest member.
In addition sliding of the sheath on the cable core is induced with resulting change in the pitch between the handling members. This change is unacceptable in systems where the cable is entrained by wheels with teeth which engage with the radial handling members.
For cables with plastic surface sheaths it is proposed to incorporate in the radial members a pin transversal to the cable to anchor them to the core. However it was found that a radial member thus realized is not satisfactory because driving it into the cable results in damage to the fibers and localized stresses resulting in breakage, even by fatigue, which considerably reduces cable life.
In the production of cables it is expedient that the core be formed from a braid with strands making a low angle with the cable axis, for example less than 45.degree., to minimize cable lengthening and raise its flexibility. Cables with loose braid of this type are not suited to coming into contact with powdery materials which would collect in large quantities between the strands. To avoid this drawback the cable can be covered with a braiding with very thick weave and therefore with high-angle fibers with respect to the cable axis.
A cable produced in this manner was however considered completely unsuited to being equipped with radial members made of thermoplastic material for direct molding on the cable. The compactness of the sheath prevents all possible catching of the plastic material on the cable core with the above mentioned drawbacks.
The purpose of the present invention is to find a solution allowing use in handling systems of a cable of the type mentioned equipped with a braided surface sheath making it suitable to receive heat molded radial members on the cable integrally constrained thereto with no possibility of sliding.